This invention relates to an attachment element for fixation to corporeal tissue and a method of manufacturing the same. Such an attachment element may be used to attach endoluminal prosthesis within arteries, veins and similar lumens. As such, the attachment element would be capable of intraluminal delivery.
A variety of endoluminal prosthesis currently exist which require fixation within corporeal lumens. Examples of such are grafts and stents. Grafts are artificial lumens which replace the natural lumen or reside within the natural lumen and isolate the natural tissue from blood flow.
Stents are semi-rigid tubular structures which may be used to maintain the patency of natural lumens or grafts. By providing scaffolding for the lumen, stents prevent collapse and occlusion. Stents are typically formed either by winding wire into a tubular structure or removing material from a solid tube.
Prior art grafts and stents have described the use of hooks to improve fixation of the prosthesis. These hooks were typically formed of bent wire attached to the prosthesis. The prior art also teaches integrally formed hooks on the prosthesis. These integral hooks are formed to be axially aligned with the prosthesis prior to deployment and forced outwardly upon intraluminal deployment.
What has not been taught by the prior art and was heretofore unknown is an integrally-formed, outwardly predisposed hook for attaching to a corporeal lumen. The present invention satisfies that need.
Briefly and in general terms, the present invention embodies an attachment or anchoring element (ie., protrusion, hook, barb) for fastening to corporeal tissues and a method of manufacturing the same. The attachment or anchoring element is formed as an integral portion of a metallic frame and has a preset outward bend or curve. The attachment or anchoring element is generally comprised of an elongated member and a pointed end. The pointed end is configured to impinge upon and possibly pierce corporeal tissue, plaque or other debris or disease.
In general, the present invention provides an improved attachment or anchoring element (which will be referred to herein as a hook for convenience) for fixation of endoluminal prosthesis. As such, the hook is configured for intraluminal delivery within a catheter or capsule. The hook and endoluminal prosthesis may then be delivered to a diseased or damaged portion of a corporeal lumen such as an artery or vein. Once delivered the hook may be compressed into or pierce the interior surface of the lumen. When compressed in such a fashion, the hook and prosthesis are securely fastened to the corporeal lumen.
There exists a variety of endoluminal prostheses which would benefit from the superior fixation provided by a hook which embodies the features of the present invention. Once such device, an abdominal aortic graft is used to treat abdominal aortic aneurysms. Such treatment requires the intraluminal delivery of the graft across the aneurysm. Once delivered the graft must be firmly attached to the surrounding tissue of the abdominal aorta. The present invention, in one possible embodiment, may be configured to provide secure leak-proof fixation for abdominal aortic grafts.
The hook may be formed integrally with the endoluminal prosthesis to be secured. It may also be formed separately and attached to the prosthesis by a variety of well-known means. The hook is typically formed from a metallic frame. This frame could be separate from the host prosthesis or be a portion thereof.
The hook is formed by cutting narrow incisions in the frame. These incisions define the elongated member and the pointed end. Laser-cutting is a well-known method of making such incisions. Once the hook is cut it can be bent outwardly such that the pointed end faces the direction in which the corporeal tissue will lie. This bend or curve in the hook may be permanently set by heating. Once set, the hook may be pressed back into the frame and the hook will spring back into the bent position when released due to its resilient nature.
There are a variety of configurations for the hook which are embodied in the present invention. The elongated member may have a constant crosssection throughout its length. It may also have a reducing cross-section near the pointed end. The pointed end may include one or more barbs. One configuration includes a single barb on either side of the pointed end, forming an arrowhead configuration. The pointed end may also be sharpened to further ensure fixation. Multiple hooks may be formed within a single frame. It is possible to form multiple hooks from a single set of incisions. Multiple hooks in opposing directions may provide superior fixation.
Other features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example the principles of the invention.